Vaillant COMBlcompact VCW 242E User manual

Vaillant Training/Logical Fault Finding Guide for all
COMBlcompact and THERMOcompact models
v
t
v
~Vaillant
HEATING,CONTROLS,HOTWATER.

;"
tWJVaillanl
HEATING,CONTROLS,HOTWATER.
Contents
~~
Guidance Notes
IICD
l' ."...
V
If
Room Sealed Fan Flued Models (RSF)
COMBlcompact
VCW 242E, 282E
THERMOcompact
VC112E, 142E, 182E,242E, 282E Ii)
)r:-'
.
'-:14
.
Balanced Flue & Open Flue Models
COMBlcompact
VCW221, 240, 280
THERMOcompact
VC110, 180, 240, 221.

t¥JVaillant
HEATING,CONTROLS,HOTWATER. [!]
Guidance Notes (should be read before using this fault finding guide)
1. Check you are using correct guide for your appliance.
See index and check model number.
2.Always start at the beginning of guide and work
through one step at a time.
3.AII guides deal with central heating (C/htg) first, then
hot water (D.HW.)
Do the same when following guides.
4. When checking 240v AC mains voltage use terminal 1
on appliance terminal strip as the neutral test point.
~5. When checking D.C. voltage use terminal 9 on
appliance terminal strip as the negative test point.
(All D.C. voltages are low voltage).
10
5
6
1
Q
7
Note 1 It is law* that any work carried out on a gas
appliance must be carried out by a competent person
who is registered with CORGI (Council for Registered
Gas Installers).
Note 2 All work involving electricity must be carried
out by a competent person who is responsible for
electrical safety checks.
*Gas Safety (Installations and Use) Regulations 1984
Gas Safety (Installations and Use) Amendment
Regulation 1990
6.ln order to use this fault finding guide ensure that the
operating mode of circulating pump is set to operating
mode (I) (selector plug adjacent to appliance terminal
strip makes electrical connection to contact one) see
diagram.
TIISI
0Gro GroG
7. Note that illustrations and pictures are shown only
once and are not duplicated again in this guide.
Each illustration/picture has been given a reference
number.
9
3
FRONT CONTROL PANEL
Key
1. Yellow neon indicating power to operator.
2. Green neon indicating operation of Diaphragm pump.
As voltage decreases to diaphragm pump so neon loses
luminosity.
3. 0.16 amp anti surge fuse.
4. Time delay adjustment (factory set 5 minutes,
adjustable 1-12 minutes).
5. Fault suppression button (ignition lockout).
6. Indicating neon (lockout).
7. 2 x 2 amp fuses (L&N).
8. Variable potentiometer controlling central heating flow
temperature only.
9. Red neon rocker switch for power on.
10. Central heating rocker switch (not fitted on VC
appliances) .
4
2
8

t¥JVaillanl
HEATING,CONTROLS,HOTWATER.
Room Sealed Fan Flued Models (RSF)
guidance note 6)
Q.
11
+
YES
+
1

:g
~....
f...l
~
~
YES
~
Cr
...
I
~Vaillant
HEATING,CONTROLS,HOTWATER.
[!]
(c) Check appliance not in time
delay (isolate power, wait 5
seconds and restore).
(d) Check anti surge fuse
(0.16 amp).
...

~
$J
Inoe. pU\pPrun1
t
YES
,
[Go ill 4
~
Check hydraulic operation OK ?
1. Hydraulic diverter valve
moves leftcloses microswitch
M2 (VCWonly)
T
~
2. Differential valve opens.
TPic14
[Goto 5
4
I',
tiJVaillanl
HEATING, CONTROLS,HOTWATER.
~NO" (a) Check 240vACacross
pump terminals
TPic10
(b) Check pump free to rotate
and not stuck
TPic11
~.
Itv
If(a) and (b) are OK.- change
pump.
I~NO
(a) Check appliance and
system full, pressurised and
vented of air.
(b) Check servo valve is in
C/htg position, return spring
holds carn down (VCW
only).
T
(c) Check for dirt, sludge,
flux or inhibitorcausTng
frothing in system
affecting:-
1. Pump performance
2. Hydraulic diverter valve
(VCW only)
3. Servo valve (VCW only)
4. Connecting tubes
5. Main heat exchanger
6. Differential valve
Pic12
M3
OPEN G
Rear view
I

~
Does applianC1
ignition?
T
~
(yellow neon glowing front
control box)
0
YES
~
~Vaillant
HEATING,CONTROLS,HOTWATER. ~
I~O~ (a) Check microswitchM2
(20v DC)is makingcontact
and closed circuit(VCW
only).
T
(d) Checkcombustion
chamber seals.
(e) Cneck air
switcn"tubes
kinkedand Sl
., top cover plate clear.
T
Pic15
(b) Check fan pressure
switch oper9tes (240v AC
:fromboth sides of switch to
neutral terminal 1) ifnot
check C to F
TPic16
(c) Check flue installation:
-Joints correctly located
- Flue not blocke(
- Terminal position
(1)Check fan working
correctly.
Ifall above OK change fan
pressure switch.

~
@J
Does burner light and
remain alight?
~
YES
~]
~Vaillant
HEATING,CONTROLS,HOTWATER.
~NO~ N;B. For lockoat (Black
button & Red Neon)
problems when no flame is
visible check A to F.
T
t
\)~rnenflame is visible prior
to lockout checkFto H only
(a). Check gas supply to
appliance live and purged.
(b). Check differential valve
open (if no return to Q4).
(c). Check20v DC across
gas operator, if available
but operator fails to open
(audible click) change
operator.
T
t
(d). Check central heating'
overheat thermostat and
connection (should be
closed circuit, if open
change component).
T b " Pic22

71
I
~
~
YES
~
Goto 8
~fjJ
YES
~Vaillant
HEATING,CONTROLS,HOTWATER.
I~O~ (a) Check standing and
working gas pressure at
appliance inlet.
TPic25
~
(c) Check voltage across
diaphragm pump (approx 6v
DC) withNTC disconnected.
TPic27
J
(b) Check diaphragm pump
operating tubes and throttle
jet clear.
TPic26
NO~ (a) TestNTC/Elebtronic
board.
Pull off NTC wire (from
D.H.W. overheat) touch it
on chassis, if burner goes
off, change NTC.
TPic29
(d) Check burner pressure
settings low and high fire rate.
TPic28
(e) Check and/or replace gas
operator.
If burner stays on change
electronic board.
(The gas operator may be
stuck open eg debris. This
symptom is very unlikely
but can be checked by
pulling offthe wire to
operator. Ifburner remains
alight then change
operator).

~Vaillant
HEATING,CONTROLS,HOTWATER.
@
(a) Check demand for hot
water-tap open and supply
pipes correct way round.
(b) Check water section
moves servo valve cam - if
not check venturi/diaphragm
of water section.
..
~o~
~
YES
!
Pic 30
(c) Check microswitCh M3
(20v DC) is making contact
and closed circuit.
.. Pic31
(d) Check hy
valve moves
microswitch r
open no eTec
through switch).
..
M3
CLOSED ~
(e) If D
check gas -
pressure at
& burner pr'
Pic 25 & Pic 28.
(1) If water fl<
insufficientc 0
adequate cold water mainO,
supply and/or blockage in
water section or DHW
~

H'
t
'r
I
I.'"
tiJVaillant
HEATING,CONTROLS,HOTWATER.
@]
Balanced Flue and Open Flue Models
COMBlcompact VCW221 , 240, 280
THERMOcompact VC11 0, 180, 240, 221
Red Rocker switch - Set to ON position
Heating Switch - Set to ON position (VCW only)
Circulating Pump - Operating mode position one (I) (see guidance note 6)
~First check central heating operation (All external controls on)
11
Can pilot light be lit and
established? I~NO~ (a) Check gas supply to
appliance live and purged.
(b) Check pilot injector,
burner and supply tubes.
... Pic33
(d) Check thermocouple
and connections.
... Pic35
~+
YES
+
~
(c) Check piezo ignitor,
leads and electrodes.
... Pic34
(e) Check central heating
overheat thermostat and
connections (should be
closed circuit, if open
change component).
Refer to Pic 22
(f) If intermittent pilot
outage occurs check flue
integrity (balanced flue)
ventilation or draughts
(open flue).
Go to 2
9

~
~
Does red neon glow in
main switch?
+
YES
t
Go to 3
~
Does pump run?
+
YES
t
Go to 4
~Vaillant
HEATING,CONTROLS,HOTWATER.
~o~
I
~o~
I
(a) Check 240v AC across
terminals 2 (L) and 1 (N)
Refer to Pic 1.
(b) Check 2 x 2 amp
appliance fuses.
Refer to Pic 2.
(c) Check 3 amp spur fuse.
If fuses OK and power
available but neon fails to
light, replace front Mother
Board.
~
(a) Check 240v AC across
pump terminals (if not check
C to F).
Refer to Pic 10.
(b) Check pump free to
rotate and not stuck - If A &
B are OK change pump.
Refer to Pic 11.
(c) Check 240v AC available
for external controls at
terminal 3, if not change
Mother Board.
Refer to Pic 5.
(d) Check demand for
heating - external controls
on, and 240v AC back to
terminal 4.
(e) Check anti surge fuse
(O.16amp). Refer to Pic 4.
(f) Check safety isolating
transformer 240v AC
primary (black/grey) and
approx. 17v AC secondary
(brown/blue). Refer to Pic 9. '"

~
Check hydraulic operation
OK?
1. Hydraulic diverter valve
moves left closes
microswitch M2 (VCW only).
Refer to Pic 13.
or
2. Differential valve closes
microswitch M4 (VC's only)
TPic36
\.,
"YES
~
Go to 5
tijVaillant
HEATING,CONTROLS,HOTWATER.
[!]
NO" (a) Check appliance and
system full, pressurised and
vented of air.
(b) Check servo valve is in
C/htg position, return spring
holds cam down (VCW
only). Refer to Pic 12.
(c) Check differential valve
and tubes.
(d) Check for dirt, flux
sludge or inhibitor in system
causing frothing affecting :-
1. Pump performance.
2. Hydraulic diverter valve
(VCWonly).
3. Servo valve (VCW only)
4. Connecting tubes.
5. Main heat exchanger.
6. Differential valve.
I

l~
~
Does burner light?
+
YES
+
Go to 6
@J
t¥JVaillanl
!~O~
I
HEATING,CONTROLS,HOTWATER.
(a) Check variable
potentiometer (boiler stat)
setting on maximum.
(b) Check appliance not in
time delay (isolate power wait
5 seconds and restore).
(c) Check Domestic Hot
Water overheat thermostat
(VCW only) - pull off bottom
white wire, if burner lights -
Replace DHW overheat.
Refer to Pic 7.
(d) Check NTC - (pull wire off
NTC sensor, if burner lights
change NTC. Refer to Pic 8.
(e) Check operation and
adjustment of microswitch M2
20v DC (VCW only).
Refer to Pic 15.
(f) Check differential valve
closes microswitch M4 20v
DC (VC only).
T
(9) Check 20v DC across gas
operator, if available but
operator fails to open (audible
click) change operator.
Refer to Pic 21
(h) Check for continuity
through gas section
microswitch M5 (20vDC)
TPic38
~
(i) Check for continuity
through main heat exchanger
overheat thermostat.
TPic39
Pie3?
0) Check small p.c.b. bridge
located bottom rear of Mother
Board.
T
.~
Does burner modulate up to high
firerateafterapprox5seconds? I~O"
~,
YES
,
Go to 7 I
(a) Check standing and
working gas pressure at
appliance inlet. Refer to Pic
25.
(b) Check diaphragm pump
operating tubes and throttle
jet clear. Refer to Pic 26.
(c) Check voltage across
diaphragm pump (approx 6v
DC) (NTC disconnected
Refer to Pic 27.
(d) Check burner pressure
settings low and high fire
rate. Refer to Pic 28.
(e) Check and/or replace
gas operator.

11
f-
.~
Does appliance modulate
down to low fire (ignition
rate) and go off?
To test
Put appliance thermostat to
no. 6, fire appliance for
central heating. Burner
should now modulate down
and shut off at approx 60°C
(see temperature gauge).
~
YES
If COMBlcompact VCW
Go to 8
If THERMOcompact VC
End of job
~&
For VCW only - is D.HW
operation OK?
::i
YES
+
End ofjob
tiJVaillant
NO"
NO"
I
HEATING, CONTROLS,HOTWATER. ~
(a) Test NTC/Electronic
board.
Pull off NTC wire (from
DHW overheat) and touch it
on chassis, if burner goes
off change NTC.
Refer to Pic 29
If burner stays on change
electronic board.
(The gas operator may be
stuck open e.g. debris.
This symptom is very
unlikely but can be checked
by pulling off the wire to the
operator. If burner remains
alight then change
operator).
(a) Check demand for hot
water - tap open and supply
pipes correct way round.
(b) Check water section
moves servo valve
cam - if not check
venturi/diaphragm of water
section. Refer to Pic3().
(c) Check microswitch M3
(20v DC). Refer to Pic 31.
(d) Check hydraulic diverter
valve moves right opening
microswitch M1 (with M1
open no electrical continuity
through switch). Refer to
Pic 32.
(e) If DHW not hot enough
check gas supply working
pressure at appliance inlet
& burner pressure. Refer to
Pic 25 & Pic 28.
(f) If water flow rate
insufficient check. for
adequate cold water main
supply and/or blockage in
water section or DHW heat
exchanger.
End of job.
13

~Vaillant
HEATING,CONTROLS.HOTWATER.
HeadOffice and Southern Region
VaillantLimited,VaillantHouse,
MedwayCityEstate,TridentClose,
Rochester,KentME24EZ
ReceptionPhone
SalesPhone
SalesFax
ServiceFreephone
ServiceFax
TechnicalAdvicePhone
TechnicalAdviceFax
TrainingPhone
0634290155
0634292310
0634712804
0800318076
0634294506
0634292392
0634294504
0634292370
VaillantLimited,
AreaTrainingCentre
LittletonHouse,AshfordRoad,
Ashford,MiddlesexTW151UU
ServiceFreephone 0800318076
WesternRegion
VaillantLimited,
DunsterRoad,ChelmsleyWood,
BirminghamB377UU
SalesPhone
SalesFax
ServiceFreephone
.
0217883366
0217797141
0800318076
VaillantLimited,Unit2,
GreatWesternBusinessPark,
ArmstrongWay,Yate,BristolBS175NG
SalesPhone 0454321736
SalesFax 0454321622
ServiceFreephone 0800318076
NorthernRegion
VaillantLimited,VaillantBuilding,
EurowayTradingEstate,WharfedaleRoad,
Bradford,WestYorkshireBD46SR
SalesPhone 0274688322
SalesFax 0274651096~
ServiceFreephone 0800318076
'.,
VaillantLimited,Block13,Unit3,
WhitesideIndustrialEstate,FactoryRoad,
Bathgate,WestLothianEH482RX
SalesPhone .0506635522
SalesFax 0506636290
ServiceFreephone 0800318076
2ndeditionFebruary'94
Designed and Produced by IMPACT Image Management 0622 721144
Vaillant cannol accept responsibility for damage as a resull 01non-observance 01this
Fault Finding Guide. Subject to alteration. (2194).